In recent years, as information electronic devices are spread, a display device having a touch panel and/or a protection member having robustness on a front surface of a display element is widely spread. The display device and the touch panel and/or the display device and the protection member are bonded therebetween by an adhesive material having the substantially equal refractive index thereto. Thereby, surface reflection between the respective members is removed, deterioration of the visibility due to the surface reflection of the outside light is suppressed or the display device is protected from an external shock, water immersion or dust.
When the touch panel and/or the protection member are arranged on the front surface of the display element, in order to suppress air bubbles from being generated upon adhesion of the adhesive material, a thick adhesive material capable of absorbing a step or a plurality of sheets of adhesive materials with being overlapped is used in the vicinity of a step between a frame holding a peripheral part of the display element and a display surface of the display element (for example, refer to 2009-8703A or 2009-116297A).
By the way, when attaching the display device disclosed in 2009-8703A or 2009-116297A to an outer housing, following problems are considered. The display device of the background art is described with reference to the drawings. FIG. 6 is a sectional view of the display device of the background art, and FIG. 7 is an enlarged view of an A part of FIG. 6. As shown in FIGS. 6 and 7, a display device 200 is shown which includes at least a backlight 201, a front frame 207 holding a display element 202 arranged at a position facing the backlight 201, a touch panel 205 held at a display surface-side of the display element 202 by first and/or second adhesive materials 211, 212 and a protection member 206 held by a third adhesive material 213 arranged on an upper surface of the touch panel 205. When attaching the display device 200 from a side surface to an outer housing 203 by a screw 204, the front frame 207 is deformed in an inside direction (a direction along which the front frame 207 presses the display device 200) of the display device 200, as shown with a first deformation direction 2071. Also, an upper surface of the front frame 207 is tensioned in a direction getting away from the display device 200 by a reaction, as shown with a second deformation direction 2072. Thereby, the second adhesive material 212 is applied with a peeling force, so that air bubbles 2020 may be generated in the first adhesive material 211 and the second adhesive material 212 in the vicinity of an opening end portion of the front frame 207. Also, a force is applied from the outer housing 203 at the display surface-side in a housing weighting direction 2031, so that the display element 202 is pressed in the vicinity of the opening end portion of the front frame 207 to thus cause display unevenness 2021.